An automatic sewing device is known from DE 32 16 528 C2, in which, prior to the actual sewing process, a workpiece holder is adjusted in size to match a workpiece to be sewn, for instance a collar or a cuff. For the purpose of automatically balancing the adjustment of size and the seam contour, the adjustment of size is detected as a measuring length and passed on to a control unit of the automatic sewing device. It is of disadvantage that an adjustment of size of the workpiece holder to match the size of each workpiece to be sewn in necessary prior to the sewing process. The workpiece holder adjustable in size has a complicated structure. The workpiece holder itself is huge and requires a correspondingly dimensioned sewing panel.
An apparatus is known from DE 89 06 434 U1 to be used in an automatic sewing device for automatically balancing the adjustment of size for collar sewing. In this case the size of a collar is detected by opto-electronic sensors, after the collar has first been put against a reference stop. Corresponding to the collar size detected, a workpiece holder consisting substantially of a stationary half-plate and of a second half-plate displaceable in longitudinal direction of the collar is automatically adjusted. This is comparatively expensive, too.
An automatic sewing device is known from DE 31 34 028 C2 to have a feeder with a workpiece holder. After a first seam contour section has been sewn, the workpiece holder is shifted on the workpiece; then a second seam contour section is sewn. The reason why the workpiece holder is shifted with the workpiece resides in that a seam contour is to be produced, of which the dimensions exceed the size of the sewing field available, i.e. the size of the area run over by the workpiece holder.